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Biomedical subjects

C H Chiu

Publications and source records attributed to C H Chiu.

At least 37 records · Page 2Linked to original sources
PubMed2001

Surgical implications of pseudomonas aeruginosa necrotizing fasciitis in a child with acute lymphoblastic leukemia.

Necrotizing fasciitis caused by Pseudomonas aeruginosa is extremely rare. Only 4 cases were reported in the literature. The authors report the occurrence of P aeruginosa necrotizing fasciitis starting out as a vulval abscess in a girl before induction chemotherapy for acute lymphoblastic leukemia. To our knowledge, this is the second case described in association with leukemia. In this case, the outcome was favorable because of early surgical intervention, confirming the diagnosis. J Pediatr Surg 36:948-950.

Child, Preschool↗
PubMed2001

Septic arthritis of the hip caused by Salmonella typhi.

We describe septic arthritis of the hip in a child with typhoid fever. The aetiological diagnosis was confirmed by a positive Widal test as well as by isolation of Salmonella typhi from joint aspirate. Treatment with ceftriaxone along with surgical drainage was successful.

Arthritis, Infectious↗
PubMed2001

Large drug resistance virulence plasmids of clinical isolates of Salmonella enterica serovar Choleraesuis.

Salmonella enterica serovar Choleraesuis generally causes systemic human salmonellosis without diarrhea, and therefore, antimicrobial treatment is essential for such patients. The drug resistance information on this organism is thus of high value. Serovar Choleraesuis usually harbors a virulence plasmid (pSCV) of 50 kb in size. Of the 16 clinical isolates identified to be serovar Choleraesuis, all except one harbored a pSCV and seven of them carried a pSCV of more than 125 kb in size. A pSCV was defined as a plasmid carrying spvC and characteristic deletions detected by PCR and by DNA-DNA hybridization (for the former criterion). The results of PCR, restriction fragment profiles, and Southern DNA-DNA hybridizations of the profiles all indicated that such larger pSCVs were derived from the 50-kb plasmid recombined with non-pSCVs found in some clinical isolates. Fifteen of the 17 strains, including a laboratory strain, were then tested for drug resistance against 16 antibiotics with E-test and the dilution method. The laboratory strain, which harbored a 50-kb pSCV and a 6-kb non-pSCV, was resistant only to sulfonamides (SUL), and its resistance gene, sulII, checked with PCR and DNA-DNA hybridization, was located on the 6-kb non-pSCV. All 14 clinical strains were resistant to multiple drugs. Of the 14, 7 were resistant to SUL, and the resistance gene was located on a plasmid. The sulII gene, but not bla(TEM-1), was carried only on the 6-kb non-pSCV. Of the remaining six large plasmids, three of 90 kb, two of 136 kb, and one of 140 kb, the last three were pSCVs and carried the other SUL gene (sulI) and the bla(TEM-1) gene. The six strains were also resistant to trimethoprim-sulfamethoxazole. None of the 50-kb pSCVs carried resistance genes. These drug resistance genes on the large pSCVs were apparently also acquired through recombination.

Bacterial Proteins↗
PubMed2001

Liver abscess caused by Klebsiella pneumoniae in siblings.

Klebsiella pneumoniae has been emerging as the leading cause of liver abscess in diabetic patients. Results of molecular typing of K. pneumoniae isolates from two siblings with liver abscess, their family members, and the environment suggest a possibility of cross infection of liver abscess by the fecal-oral route within diabetic patients.

Adolescent↗
PubMed2001

Effect of N(G)-nitro-L-arginine methyl ester on intestinal permeability following intestinal ischemia-reperfusion injury in a rat model.

Subclinical intestinal ischemia-reperfusion injury (IRI) causes an increase in mucosal permeability and may represent an early event in the pathogenesis of necrotizing enterocolitis in premature infants. Previous studies suggested that continuous, endogenous formation of nitric oxide (NO) maintains the mucosal integrity of the intestine, thus protecting the gut from injuries from blood-borne toxins and tissue-destructive mediators. This study was undertaken to assess whether the inhibition of NO production causes an increase in intestinal permeability in rats following IRI. Sprague-Dawley rats weighing 200-300 g were divided into 4 groups: (1) untreated group (normal control); (2) ischemia-reperfusion group; (3) early N(G)-nitro-L-arginine methyl ester (L-NAME), a specific inhibitor of NO production, treatment group, and (4) late L-NAME treatment group. Transient IRI was induced by 30-min occlusion, followed by reperfusion of the isolated ileal loop. The L-NAME was administered 15 min before and after mesenteric ischemia as a 25-mg/kg bolus. Fluorescein isothiocyanate-dextran (FITC-D) was used to quantitatively assess the alteration in mucosal permeability of the intestine. There was no significant increase in the portal vein FITC-D level among normal controls, ischemia-reperfusion group and late L-NAME-treated group, but there was an approximately 6-fold increase in the early L-NAME treatment group. The pathological features of the intestine following IRI include denudation of the villus epithelium and reduction of villus height, associated with marked inflammatory cell infiltration over the lamina propria. These results suggest that endogenous NO may play a role in the protecting intestinal integrity after IRI.

Animals↗
PubMed2001

Epstein-Barr virus-associated hemophagocytic syndrome masquerading as lymphoma: a case report.

Virus-associated hemophagocytic syndrome (VAHS) is a non-neoplastic, generalized histiocytic proliferation with prominent hemophagocytosis associated with a systemic viral infection. Although Epstein-Barr virus (EBV) is one candidate virus for this association, thorough serologic and molecular biologic studies to determine the presence of the viral infection have been lacking in many reports. Whereas elevated liver function tests are common findings in patients with VAHS, exudative ascites and abdominal lymphadenopathy are rare. We describe a case of EBV-AHS masquerading as lymphoma in which treatment with intravenous immunoglobulins was associated with complete clinical remission at 2 years and 6 months after the onset. Regardless of the exact mechanism responsible for ascites formation in VAHS, this case adds support to the possible involvement of EBV in patients with abdominal lymphadenopathy and ascites.

Child, Preschool↗
PubMed2001

Childhood and adolescent tuberculosis in northern Taiwan: an institutional experience during 1994-1999.

UNLABELLED: This study evaluated the clinical characteristics of childhood and adolescent tuberculosis (TB) at the end of the twentieth century in a referral children's hospital in northern Taiwan. The hospital charts were reviewed retrospectively of children/adolescents aged less than 18 y who were seen in a children's hospital in northern Taiwan between 1994 and 1999 and diagnosed with TB. A total of 62 individuals was diagnosed during this period. The patients' demographic data, presenting symptoms, clinical features, bacteriological results, drug susceptibility and tuberculin skin-test results were analysed. Most diagnosed cases lay in one of two main age ranges, younger than 5 y and adolescents. The presenting symptoms of study subjects were typically non-specific. Bone involvement occurred for 21 patients (33.9%) and was the most common extrapulmonary manifestation. Mycobacterium tuberculosis was isolated from 47 patients (75.8%). Five isolates were resistant to pyrazinamide, three to streptomycin and one to isoniazid, but no multidrug resistant isolates of TB were detected from culture-proven cases. Seventeen of 47 (36.2%) culture-proven patients revealed negative acid-fast staining initially but, subsequently, M. tuberculosis was isolated from various clinical specimens using a standard method at a later date. The tuberculin skin test was positive for 24 of 32 patients (75%) who received such an examination. CONCLUSION: Extrathoracic TB was more common in children below 5 y of age than their adolescent counterparts, and chiefly involved the peripheral long bones. The potential drug resistance of M. tuberculosis in childhood and adolescent TB did not appear to have been a major problem in northern Taiwan before the year 2000.

Adolescent↗
PubMed2001

Characteristics of group A streptococcal bacteremia with comparison between children and adults.

This retrospective study aimed to compare the characteristics of group A streptococcal bacteremia in children and adults. A total of 76 (12 children and 64 adults) patients with group A streptococcal bacteremia treated from October 1995 through September 2000 at the Linko Chang Gung Memorial Hospital were included. The mean age was 47.6 years (range, 12 days-90 years). Forty-four (57.9%) patients had predisposing medical conditions. Malignant cancer (23.7%) and diabetes (22.4%) were the 2 most common conditions, which occurred only in adults. Two (16.7%) children had chickenpox associated with secondary group A streptococcal bacteremia. Skin and soft tissue infection (60.5%) was the most common clinical manifestation. The mortality rate related to group A streptococcal bacteremia was 25%. Twelve patients met the criteria of streptococcal toxic shock syndrome and 6 (50%) were children (p<0.05). Despite immediate and aggressive treatment, mortality due to streptococcal toxic shock syndrome was 66.7%. The incidence of streptococcal toxic shock syndrome was much higher in children (50%) than in adults (9.4%). Early diagnosis of invasive group A streptococcal infections and streptococcal toxic shock syndrome requires awareness of the presentations and a high level of suspicion. For fulminant group A streptococcal infection, a combination of a beta-lactam antibiotic plus clindamycin and/or adjuvant therapy with intravenous immunoglobulin is recommended.

Adolescent↗
PubMed2001

Deep neck infections in children.

From December 1989 through 1998, a total of 68 children with deep neck infection were enrolled into this study. The mean age was 5.9 years (range, 1 month-15.8 years). Infections in the retropharyngeal space (36.7%) were most common, followed by parapharyngeal space (30.8%), peritonsillar space (20.6%), and submandibular space (11.9%). Fever, neck pain, and swelling were the most frequent symptoms. The most common pathogens were viridans streptococci (41%, 16/39) and Staphylococcus aureus (26%, 10/39). Other isolates included Prevotella spp., Veillonella spp., Klebsiella pneumoniae, Escherichia coli, Morganella spp., and Enterobacter spp. Mixed infection was found in 46% (18/39) of patients. The mean duration of hospitalization was 12.4 days (range, 2-45 days). Complete resolution was achieved in 61 (89.7%) children. Complications occurred in 7 patients, including recurrence, mediastinal spread, bacteremia, and suppurative thyroiditis; the patient with mediastinal spread plus bacteremia died. Five patients had congenital cyst and 4 of them had complications or recurrence/relapse. In conclusion, infections in the retropharyngeal space and polymicrobial infections were most common in deep neck infection of Taiwan children.

Anti-Bacterial Agents↗
PubMed2000

Gene conversion may aid adaptive peak shifts.

Gene conversion is often viewed as a homogenizing force that opposes adaptive evolution. The objective of this study is to suggest a potential role for gene conversion in adaptive evolution of proteins through aiding the transfer of a population from one adaptive peak to another. Our hypothesis starts with the observation that a tandem gene duplication may result in an extra gene copy that is released from selective constraints. In such cases, individually deleterious mutations may accumulate on the extra copy of the gene, and through gene conversion these mutations may subsequently be presented to the functioning gene for selection en masse. Thus, groups of mutations that jointly confer a selective advantage may regularly be made available for selection. We present a mathematical model of this process and identify the range of rates of gene conversion, gene duplication and mutation under which it may operate. The results indicate that the process may be biologically feasible if the rate of appearance of the potentially beneficial mutations is not too small in relation to the rates of null mutation and of gene conversion. This process appears to be a possible mechanism for effecting adaptive peak shifts in large populations. We show that all the evolutionary steps in the proposed model may have occurred in the evolution of primate gamma -globin genes. We suggest that hide-and-release mechanisms for genetic variation may constitute a more general principal of evolvability.

Adaptation, Physiological↗
PubMed2000

Humans and old world monkeys have similar patterns of fetal globin expression.

The expression of epsilon- and gamma-globin mRNA and protein has been determined in three Old World monkey species (Macaca mulatta, Macaca nemestrina, and Cercopithecus aethiops). Using RT-PCR with primers for epsilon- and gamma-globin, both mRNAs were detected in early fetal stages, whereas at 128 days (85% of full term), only gamma was expressed. High-performance liquid chromatography was used for separation and quantitation, and matrix-assisted laser desorption/ionization mass spectrometry was used for identification of globin polypeptides. An alpha-globin polymorphism was observed in all of the species examined. During fetal life, gamma-globin was the predominant expressed beta-type globin. The red blood cells of infants still contained substantial amounts of gamma-globin, which declined to negligible levels in 14 weeks as beta-globin expression reached adult values. The ratio of gamma1- to gamma2-globins (equivalent to Ggamma/Agamma in humans) was approximately 2.5, similar to the Ggamma/Agamma ratio observed in humans. Thus, gamma-globin gene expression in these Old World monkeys species has three features in common with human expression: expression of both duplicated gamma genes, the relative preponderance of gamma1 over gamma2 expression, and the delay of the switch from gamma- to beta-globin until the perinatal period. Thus, the catarrhines seem to share a common pattern of developmental switching in the beta-globin gene cluster, which is distinct from the timing of expression in either prosimians or the New World monkeys. Our results indicate that an Old World monkey, such as Rhesus, could serve as a model organism (resembling humans) for experimentally investigating globin gene expression patterns during the embryonic, fetal, and postnatal stages.

Animals↗
PubMed2000

Evolution of Hoxa-11 in lineages phylogenetically positioned along the fin-limb transition.

HOXA11 is a transcription factor implicated in paired appendage development. To identify signatures of evolutionary change in the structural, and putative functional, domains of HOXA11, we studied its evolution in tetrapod and nontetrapod lineages that represent approximately 1.5 billion years of evolutionary time. Here, Hoxa-11 gene proper sequences were determined for frog (Xenopus tropicalis), coelacanth (Latimeria chalumnae), common zebrafish (Danio rerio; Hoxa-11a and Hoxa-11b paralogs), and giant zebrafish (D. aequipinnatus; Hoxa-11b) and aligned against previously published Hoxa-11 sequences of human, mouse, chick, and newt. Based on aligned Hoxa-11 amino acid sequences, the protein was demarcated into three segments: Domains I (N-terminal) and III (homeobox + C-terminal), which varied slightly in rates and patterns of evolution, and a variable, overall hydrophilic region (HyD), which partially overlaps with Domain I. As judged by character reconstructions of HOXA11 Domains I and III, no significant changes in rates of coding sequence evolution occurred in tetrapods (frog and chick), relative to coelacanth (a lobe-finned fish), i.e., across the fin-limb transition. Accelerated rates of Hoxa-11 coding sequence evolution were observed for the mammalian and newt lineages. This was shown to be a gene-specific phenomenon. The duplicated Hoxa-11a and Hoxa-11b genes of zebrafish exhibited accelerated rates of evolution and accumulated substitutions at sites that are conserved among coelacanth and all tetrapods examined. Amino acid sequence comparisons of the HyD of HOXA11 suggested that a putative repressor subdomain, containing stretches of consecutive alanine residues, emerged within the tetrapods. A high degree of nucleotide conservation in the 5' half of the Hoxa-11 intron was observed for tetrapod and nontetrapod lineages. Using electrophoretic mobility shift assays, a 35-bp intron sequence, which is 100% conserved in all Hoxa-11 loci except for the zebrafish Hoxa-11a paralog, was found to bind protein(s) in HeLa and chick whole-cell extracts.

Alanine↗
PubMed2000

Necrotising pneumonitis in children.

UNLABELLED: We retrospectively analysed the clinical features and outcome of children under 17 years of age with necrotising pneumonitis (NP). The radiographs and CT scans of the chest of children under 17 years of age between July 1995 and March 1999 who had complicating community-acquired pneumonia were reviewed. CT scans were obtained for persistent fever, respiratory distress and sepsis despite empiric antibiotic therapy and closed tube drainage. A total of 21 children had the radiographic features of NP of whom 11 (52%) patients were successfully managed using antibiotic therapy with or without closed tube drainage. Ten patients required thoracoscopic decortications and/or lysis of pleural adhesions or debridement of empyema due to refractory pleural sepsis, failure of pulmonary re-expansion and persistent air-leaks. The most common pathogens identified were Streptococcus pneumoniae (n = 3), Staphylococcus aureus (n = 2), and Haemophilus influenzae type b (n = 2). The days of hospital stay, duration of fever and days of C-reactive protein return to normal were significantly less for the medically versus the surgically treated children (P < 0.05). CONCLUSION: The clinical course of necrotising pneumonitis in children following complicated pneumonia is often prolonged despite adequate antibiotic therapy. Necrotising pneumonitis with co-existing multiple loculations, pneumothorax/ bronchopleural fistula in the empyema and extensive pleural peel are poor prognostic factors for medical therapy. Thoracoscopic removal of loculated empyema, lysis of adhesions and/or decortication are effective in relieving tachypnoea, chest pain, and controlling fever and improve the outcome, especially in children with empyema.

Adolescent↗
PubMed2000

A recombinogenic targeting method to modify large-inserts for cis-regulatory analysis in transgenic mice: construction and expression of a 100-kb, zebrafish Hoxa-11b-lacZ reporter gene.

The identification of cis-sequences responsible for spatiotemporal patterns of gene expression often requires the functional analysis of large genomic regions. In this study a 100-kb zebrafish Hoxa-11b-lacZ reporter gene was constructed and expressed in transgenic mice. PAC clone 10-O19, containing a portion of the zebrafish HoxA-b cluster, was captured into the yeast-bacterial shuttle vector, pPAC-ResQ, by recombinogenic targeting. A lacZ reporter gene was then inserted in-frame into exon 1 of the zfHoxa-11b locus by a second round of recombinogenic targeting. Expression of the zfHoxa-11b-lacZ reporter gene in 10.5 d.p.f. transgenic mouse embryos was observed only in the posterior portion of the A-P axis, in the paraxial mesoderm, neural tube, and somites. These findings demonstrate the utility of recombinogenic targeting for the modification and expression of large inserts captured from P1/PAC clones.

Animals↗
PubMed2000

Analysis of polycyclic aromatic hydrocarbons in sediment reference materials by microwave-assisted extraction.

The microwave-assisted extraction (MAE) of polycyclic aromatic hydrocarbons (PAHs) from harbor sediment reference material EC-1, marine sediment reference material HS-2 and PAH-spiked river bed soil was conducted. The extraction conditions for EC-1 were carried out at 70 degrees C and 100 degrees C under pressure in closed vessels with cyclohexane acetone (1:1), cyclohexane-water (3:1), hexane acetone (1:1), and hexane-water (3:1) for 10 min. A comparison between MAE and a 16-h Soxhlet extraction (SX) method showed that both techniques gave comparable results with certified values. MAE has advantages over the currently used Soxhlet technique due to a faster extraction time and lower quantity of solvent used. The consumption of organic solvent of the microwave method was less than one-tenth compared to Soxhlet.

Acetone↗